As is known in the art, computers can display maps having map symbols thereon to describe the location of objects and personnel. Particularly for maps associated with military applications, map symbols can include objects such as aircraft, and groups of personnel such as battalions. As a computer map display is “zoomed out” by the operator, the map symbols are sometimes displayed so close together that a person viewing the map and the map symbols cannot effectively visualize the symbols, and cannot understand the meaning intended to be conveyed by the map symbols. In this case, the symbols are said to be “cluttered.”
U.S. Pat. No. 5,553,209 to Johnson et al., entitled Method for Automatically Displaying Map Symbols, and assigned to the assignee of the present invention, discloses a method for de-cluttering displayed map symbols as the display is zoomed out. The Johnson method can de-clutter symbols that would otherwise be on top of one another. For example, where a map display indicates six individual identical aircraft in close proximity when zoomed in, when zoomed out, rather than indicating six aircraft symbols on top of each other, the Johnson method can resolve the overlap and display a single aircraft symbol. This example is indicated in FIGS. 5A–5D of the Johnson patent.
The Johnson method can also de-clutter symbols that are not identical. Particularly when applied to military map displays, symbols may be related to each other in a hierarchy. For example, a symbol that indicates the position of an infantry company is at a lower level of hierarchy than a symbol that indicates an infantry battalion, where the latter is known to consist of two infantry companies. The Johnson method can indicate the several infantry company symbols individually when the map display is zoomed in, and can resolve and replace these multiple symbols to a single infantry battalion symbol when the map display is zoomed out. Similarly, the Johnson method can indicate symbols at progressively higher levels of hierarchy as the display is further zoomed out. To continue the given example, two infantry battalion symbols in close proximity can be indicated as a single infantry brigade symbol when further zoomed out. The Johnson method provides a de-cluttered map display that automatically adjusts the level of de-cluttering for each amount of display zoom. The hierarchy of this example is given in FIGS. 2B and 6A–6B of the Johnson patent.
However, it should be recognized that the Johnson method cannot de-clutter symbols that are neither of the same type nor related in a hierarchy. The Johnson method will not, for example, de-clutter an aircraft symbol corresponding to an individual aircraft that is overlapping or in close proximity to a battalion symbol, corresponding to a number of personnel. Unrelated symbols remain cluttered and difficult to view even with the Johnson method.
Though the Johnson method provides a map display for which many symbols are more easily viewed by a person viewing a map, such as a map computer operator, some information that would otherwise be provided to the operator is lost as the symbols are de-cluttered. The information associated with the underlying levels of the hierarchy in a de-cluttered symbol are not visible to the operator. The information not visible can include data such as type of underlying assets (companies, battalions, aircraft, etc.), cost of underlying individual assets, number of underlying personnel, exact map position of underlying assets or personnel groups, etc.
For map displays in which the Johnson method is not used, it is well known that map display symbols can become cluttered as the display is zoomed out. Where the map display symbols are on top of each other, the operator may not be able to visualize the map display symbols, nor any information normally displayed in association with the cluttered symbols. Furthermore, for those unrelated symbols that the Johnson method cannot de-clutter, the Johnson method provides no improvement to operator visualization.
It would, therefore, be desirable to provide a system which allows a map operator to see information otherwise hidden by a method such as the Johnson method. It would further be desirable to provide a system which can display data associated with cluttered symbols that have not been de-cluttered by a method such as the Johnson method. It would still further be desirable to provide a system for displaying data that represents single entities and that are visually distinguishable.